With the rapid development of the national economy, the conflict between the increasing vehicle population and the limited road area is increasingly outstanding. In order to solve this conflict, a most important part, besides intensively building roads, is increasing the utilization efficiency of the existing roads. On this background, the ITS is becoming a hot point of research and development in today's world.
No-stop ETC system and its technology is an important part of the ITS and an important technical means to solve the problems in toll roads, such as traffic congestion, traffic jam, and improve the operation security and efficiency of the existing roads. ETC system is especially suitable for the environments such as highways or bridges and tunnels with heavy traffic. With this system, toll can be implemented without stopping the vehicles, and the vehicles are allowed to pass with high speed, so the traffic capacity of the highway is largely increased; Electronic of the highway toll can decrease the cost of toll management and help to increase the operative efficiency of the vehicles; Due to the large scale increase of the traffic capacity, the size of toll station can be decreased and the capital construction cost and management cost can be saved. According to the related research, the traffic capacity of the existing toll roads can be increased for about 4 to 5 times if the ETC system is applied, thereby saving a large amount of manpower, material resources and financial power. According to the statistics of the related institutions, more than one hundred million yuan for cost of gasoline which is wasted during stopping and waiting for tolling can be saved annually only in the area of Guangzhou.
A lot of research has been done in the field of ETC, for example, Chinese patent ZL99118307.X disclosed a toll collection system which collecting the toll by equipping the vehicle with an on-board unit loaded with an IC card to wirelessly communicate with the device installed at the toll station. The device at the toll station can send the information representing if there is or how many wireless communication devices on the next stage to the on-board unit by wireless communication, and after communicated with all wireless communication devices in the device at the toll station, writing are processed on the IC card. Additionally, the patent application 03145082.2 disclosed a card processing system and method for the toll roads. The toll system includes: card processor installed at the toll station and used to process the toll, having an antenna unit to wirelessly communicate with the IC card for card processing; the antenna unit installed on both sides of the road of the toll station to wirelessly communicate with the IC card for card processing; the type-recognition device used to recognize the type of the vehicle driving in the driveway; And the driveway controller used to select the antenna unit for card processing and controlling the card processing according to the recognized type of the vehicle. There are similar patents or patent applications. But the wireless communication technology applied by the present ETC systems is generally microwave non-touch ID card identification technology, namely the RF identification technology (RFID) used in the ETC system. However, the cost of this microwave non-touch ID card identification system, especially the roadside equipment (RSE), is very high. The current price of RSE is hundreds of thousands RMB, and the cost of the whole system even reaches millions of RMB. It can be seen that cost becomes an important bottleneck to restrict the large-scale application and the development of the present ETC system.
On the other hand, with the development of the communication technology, wireless local area network (WLAN) technology is gradually becoming mature. WLAN is the computer local area network applying wireless media transmission, and the standard applied is IEEE802.11 serial. In the range of medium and short distance, WLAN technology can offer high efficient, good quality and low cost broadband access services for the mobile or semi-mobile users. Compared with the RFID technology, WLAN technology has the outstanding advantages of simple installation, short construction period and low cost. However, WLAN technology is mainly applied for the interconnection of WLAN in the range of 50 m to 100 m, and the network terminals are in the condition of static or low-speed moving (lower than 5 km/h). While in the ETC system, the moving speed of the mobile terminal is generally higher than 30 km/h. Therefore, WLAN technology is generally considered as not suitable for the ETC system. There is no precedent for applying WLAN for wireless communication in the present ETC system.